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ULTRAVIOLET RADIATION DOWN-REGULATES ALLERGY IN BALB/C MICE
Citation:
Ward, MDW, D M. Sailstad, D L. Andrews, E H. Boykin, AND MJK Selgrade. ULTRAVIOLET RADIATION DOWN-REGULATES ALLERGY IN BALB/C MICE. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH - PART A: CURRENT ISSUES. Taylor & Francis, Inc., Philadelphia, PA, 67(1):73-85, (2004).
Description:
ULTRAVIOLET RADIATION SUPPRESSES ALLERGY IN BALB/C MICE
Marsha D.W. Ward+ *, Denise M. Sailstad+, Debora L. Andrews, Elizabeth H. Boykin, and MaryJane K. Selgrade
ABSTRACT
The immunosuppressive effects of exposure to ultraviolet radiation (UVR) are well known and the underlying mechanisms have been studied extensively. UVR alters antigen presentation such that T-helper (Th) 1, but not Th2, cell activation is impaired. The suppression of Th1 appears to account for UVR suppression of both contact hypersensitivity (CH) and delayed type hypersensitivity (DTH) responses and increased susceptibility to certain infections and tumor development. The underlying mechanisms suggest that Th2 mediated responses associated with immediate-type hypersensitivity and allergic lung disease should be unchanged or possibly enhanced by UV. We tested the hypothesis that UVR exposure enhances allergic lung disease in BALB/C mice. We assessed effects of UVR on both sensitization and elicitation of respiratory hypersensitivity using a crude extract of the fungus Metarhizium anisopliae (MACA) as our allergen. To study the effect of UVR on sensitization BALB/C mice were dorsally shaved 24 hrs. before each of two sham or UVR (8 KJ/m2) exposures. Three days after each dorsal UVR/sham exposure the mice were treated intratracheally (IT) with MACA or vehicle (Hank?s Balanced Salt Solution). The mice received a third IT treatment 21 days after the first sensitization (D21). Serum and bronchoalveolar lavage fluid (BALF) were harvested on D21 (i.e., before last IT instillation), D22, D24, and D28. UVR exposure suppressed BALF total cell counts, eosinophil influx and total IgE and serum total IgE, when compared to the sham-UVR controls. Separate groups of mice were treated IT four times with MACA on D0, D14, D21, D28 as above to study the effect of UVR on elicitation. These mice received one UVR (8 KJ/m2) or sham-UVR exposure 3 days before the 4th IT treatment (D28). Serum and BALF were harvested on D24, D28 (i.e., before last IT instillation), D29, D31, and D35. There were no differences observed attributable to UVR exposure in these previously sensitized mice. These data suggest that UVR exposure prior to sensitization suppresses allergic responses but has no effect on the elicitation of allergic responses in previously sensitized individuals. Consequently, there is no evidence that exposure to UVR enhances the induction or expression of allergic lung disease.